1. Field of the Invention
This invention relates to new and useful improvements in high pressure shut-off valves and more particularly to an improved shut off-valve of in-line construction.
2. Brief Description of the Prior Art
Shut-off valves for controlling high pressure fluids and gases are well known in the art. Most shut-off valves, however, have been of an angle type construction or, if of an in-line construction, have not been capable of sealing adequately for very high pressure operation.
McCarthy U.S. Pat. No. 1,001,970 discloses a high pressure shut-off valve having an angle body construction with a sleeve type valve plug. The valve sleeve has upper and lower sealling gaskets which are compressed in valve closing movement but which do not seal completely around the valve plug assembly.
Collins U.S. Pat. No. 2,130,614 discloses an in-line valve having a vertically moving valve plug which operates through a horizontally disposed valve port. The valve member is inadequately packed for high pressure operation.
Penick U.S. Pat. No. 2,385,463 discloses an in-line valve with a vertically movable plug having a pair of separately movable valve discs movable by compression of a supporting rubber sleeve into sealing engagement with the wall of the valve cavity.
McWhorter U.S. Pat. No. 2,552,991 discloses an in-line valve, similar to Penick's, with a vertically movable plug having a pair of separately movable valve discs movable by compression of a supporting rubber sleeve into sealing engagement with the wall of the valve cavity. Wilson U.S. Pat. No. 3,013,825 discloses a wire line stripper having a rubber stripping element operated by line pressure to strip the liquid from the line.
Miller U.S. Pat. No. 3,084,898 discloses a valve assembly in which line pressure is used in valve closing operation.
Wing U.S. Pat. No. 3,115,329 shows a pressure operated valve having a piston with a peripheral rubber seal.
Bolling U.S. Pat. No. 3,353,783 discloses an in-line valve having a vertically movable plug valve assembly. The plug valve assembly is inadequately sealed for high pressure operation. This valve does show a movable valve seat which is compressed by line pressure against the valve member.
Gruber U.S. Pat. No. 3,377,048 discloses a tap valve of the type used for controlling water in sinks or tubs. This valve includes an arrangement to apply line pressure against the valve member in the closing position.